Showing 1–34 of 34 results for author: Khusanova, Y

Kiloparsec-Scale Alignment of a Radio Jet with Cool Gas and Dust in a z~6 Quasar

Authors: Fabian Walter, Eduardo Banados, Chris Carilli, Marcel Neeleman, Thomas Connor, Roberto Decarli, Emanuele Paulo Farina, Yana Khusanova, Chiara Mazzucchelli, Romain Meyer, Emmanuel Momjian, Hans-Walter Rix, Sofia Rojas-Ruiz, Bram Venemans

Abstract: We present high-angular resolution (0.068", ~400pc) ALMA imaging of the [CII] line and dust continuum emission of PSO J352.4034-15.3373, a radio-loud quasar at z=5.83. The observations reveal a remarkably close match between the orientation of the [CII] and thermal dust emission mapped by ALMA, and radio synchrotron emission of a radio jet previously mapped by the VLBA. This narrow alignment exten… ▽ More We present high-angular resolution (0.068", ~400pc) ALMA imaging of the [CII] line and dust continuum emission of PSO J352.4034-15.3373, a radio-loud quasar at z=5.83. The observations reveal a remarkably close match between the orientation of the [CII] and thermal dust emission mapped by ALMA, and radio synchrotron emission of a radio jet previously mapped by the VLBA. This narrow alignment extends over ~4kpc, reminiscent of the well-studied 'alignment effect' in lower-redshift radio galaxies. The [CII] kinematics show a linear increase in velocity with galactocentric radii up to ~200 km/s at r=2kpc, consistent with bulk motions within the galaxy potential, and not relativistic jet motions. The kinematics and respective morphologies are consistent with a picture in which the relativistic jet injects energy into the interstellar medium (potentially leading to subsequent star formation), giving rise to the observed alignment and significant (> 100 km/s) [CII] velocity dispersion within the host galaxy on kiloparsec scales. Indeed, the astonishingly close alignment and narrow linearity of the radio jet with the [CII] and dust emission are hard to conceive without some fundamental relationship between the two. △ Less

Submitted 31 March, 2025; originally announced March 2025.

Comments: Accepted for publication in the ApJ Letters

First Measurements of Black Hole Accretion and Radio-jet Timescales in a Young Quasar at the Edge of Reionization

Authors: Sofía Rojas-Ruiz, Emmanuel Momjian, Frederick B. Davies, Eduardo Bañados, Anna-Christina Eilers, Sarah B. Bosman, Bhargav Vaidya, Chris Carilli, Chiara Mazzucchelli, Thomas Connor, Yana Khusanova

Abstract: We present the first study dedicated to measuring the timescales for black hole accretion and jet launch in a quasar at the edge of Reionization, PSO J352.4034-15.3373 at z = 5.832 $\pm$ 0.001. Previous work presented evidence of the strong radio synchrotron emission from the jet affecting the host galaxy dust-dominated continuum emission at $ν_{\rm rest}=683$ GHz ($ν_{\rm obs}=100$ GHz), implying… ▽ More We present the first study dedicated to measuring the timescales for black hole accretion and jet launch in a quasar at the edge of Reionization, PSO J352.4034-15.3373 at z = 5.832 $\pm$ 0.001. Previous work presented evidence of the strong radio synchrotron emission from the jet affecting the host galaxy dust-dominated continuum emission at $ν_{\rm rest}=683$ GHz ($ν_{\rm obs}=100$ GHz), implying a break in the synchrotron spectrum. In this work, we present quasi-simultaneous observations at 1.5\, GHz - 42\,GHz with the Karl G. Jansky Very Large Array (VLA), and derive a frequency break at $ν^{\rm break}_{\rm rest} = 196.46$ GHz ($ν^{\rm break}_{\rm obs} = 28.76$ GHz). Modeling these observations, we calculate the jet spectral aging from the cooling of electrons to be $t_{\mathrm{spec}}\sim 580$ yr. From this measurement, we approximate the dynamical age $t_{\mathrm{dyn}}$ to be $\sim2,000$ yr, implying a recent jet ejection. We compare the jet timescale to the quasar's lifetime ($t_{\mathrm{Q}}$) that indicates the duration of the latest black hole accretion event and is derived from the proximity zone size in the rest-UV/optical spectrum. However, a ghostly Damped Ly$α$ (DLA) system affects this measurement yielding an upper limit of $t_{\mathrm{Q}} \lesssim 10^4$ yr, consistent with the jet lifetime and indicative of a young quasar. This suggests that the triggering of a UV-bright quasar phase may occur within comparable timescales as the launch of a relativistic radio jet. Therefore, we may be witnessing an early stage of black hole and jet interactions in a quasar during the first gigayear of the universe. △ Less

Submitted 20 March, 2025; originally announced March 2025.

Comments: 20 pages, 9 figures, submitted to ApJ

Ultra High-Redshift or Closer-by, Dust-Obscured Galaxies? Deciphering the Nature of Faint, Previously Missed F200W-Dropouts in CEERS

Authors: G. Gandolfi, G. Rodighiero, L. Bisigello, A. Grazian, S. L. Finkelstein, M. Dickinson, M. Castellano, E. Merlin, A. Calabrò, C. Papovich, A. Bianchetti, E. Bañados, P. Benotto, M. Catone, F. Buitrago, E. Daddi, G. Girardi, M. Giulietti, M. Hirschmann, B. W. Holwerda, P. Arrabal Haro, A. Lapi, R. A. Lucas, Y. Lyu, M. Massardi , et al. (20 additional authors not shown)

Abstract: The James Webb Space Telescope (JWST) is revolutionizing our understanding of the Universe by unveiling faint, near-infrared dropouts previously beyond our reach, ranging from exceptionally dusty sources to galaxies up to redshift $z \sim 14$. In this paper, we identify F200W-dropout objects in the Cosmic Evolution Early Release Science (CEERS) survey which are absent from existing catalogs. Our s… ▽ More The James Webb Space Telescope (JWST) is revolutionizing our understanding of the Universe by unveiling faint, near-infrared dropouts previously beyond our reach, ranging from exceptionally dusty sources to galaxies up to redshift $z \sim 14$. In this paper, we identify F200W-dropout objects in the Cosmic Evolution Early Release Science (CEERS) survey which are absent from existing catalogs. Our selection method can effectively identify obscured low-mass ($\log \text{M}_* \leq 9$) objects at $z \leq 6$, massive dust-rich sources up to $z \sim 12$, and ultra-high-redshift ($z > 15$) candidates. Primarily relying on NIRCam photometry from the latest CEERS data release and supplementing with Mid-Infrared/(sub-)mm data when available, our analysis pipeline combines multiple SED-fitting codes, star formation histories, and CosMix - a novel tool for astronomical stacking. Our work highlights three $2<z<3$ dusty dwarf galaxies which have larger masses compared to the typical dusty dwarfs previously identified in CEERS. Additionally, we reveal five faint sources with significant probability of lying above $z>15$, with best-fit masses compatible with $Λ$CDM and a standard baryons-to-star conversion efficiency. Their bi-modal redshift probability distributions suggest they could also be $z<1.5$ dwarf galaxies with extreme dust extinction. We also identify a strong line emitter galaxy at $z \sim 5$ mimicking the near-infrared emission of a $z \sim 13$ galaxy. Our sample holds promising candidates for future follow-ups. Confirming ultra high-redshift galaxies or lower-z dusty dwarfs will offer valuable insights into early galaxy formation, evolution with their central black holes and the nature of dark matter, and/or cosmic dust production mechanisms in low-mass galaxies, and will help us to understand degeneracies and contamination in high-z object searches. △ Less

Submitted 16 January, 2026; v1 submitted 4 February, 2025; originally announced February 2025.

Comments: Accepted for publication by Astronomy & Astrophysics

NuSTAR observations of a varying-flux quasar in the Epoch of Reionization

Authors: Lea Marcotulli, Thomas Connor, Eduardo Bañados, Peter G. Boorman, Giulia Migliori, Brian W. Grefenstette, Emmanuel Momjian, Aneta Siemiginowska, Daniel Stern, Silvia Belladitta, C. C. Cheung, Andrew Fabian, Yana Khusanova, Chiara Mazzucchelli, Sofía Rojas-Ruiz, C. Megan Urry

Abstract: With enough X-ray flux to be detected in a 160s scan by SRG/eROSITA, the $z = 6.19$ quasar CFHQS J142952+544717 is, by far, the most luminous X-ray source known at $z > 6$. We present deep (245 ks) NuSTAR observations of this source; with $\sim180$ net counts in the combined observations, CFHQS J142952+544717 is the most distant object ever observed by the observatory. Fortuitously, this source wa… ▽ More With enough X-ray flux to be detected in a 160s scan by SRG/eROSITA, the $z = 6.19$ quasar CFHQS J142952+544717 is, by far, the most luminous X-ray source known at $z > 6$. We present deep (245 ks) NuSTAR observations of this source; with $\sim180$ net counts in the combined observations, CFHQS J142952+544717 is the most distant object ever observed by the observatory. Fortuitously, this source was independently observed by Chandra $\sim110$ days earlier, enabling the identification of two nearby (30'' and 45'' away), fainter X-ray sources. We jointly fit both Chandra and NuSTAR observations--self-consistently including interloper sources--and find that, to greater than 90% confidence, the observed 3-7 keV flux varied by a factor of $\sim2.6$ during that period, corresponding to approximately two weeks in the quasar rest-frame. This brightening is one the most extreme instances of statistically significant X-ray variability seen in the Epoch of Reionization. We discuss possible scenarios that could produce such rapid change, including X-ray emission from jets too faint at radio frequencies to be observed. △ Less

Submitted 13 January, 2025; originally announced January 2025.

Comments: 16 pages, 7 Figures, 3 Tables; accepted for publication in the Astrophysical Journal Letters (ApJL)

A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE): Spectroscopically Complete Census of Obscured Cosmic Star Formation Rate Density at $z=4-6$

Authors: Fengwu Sun, Feige Wang, Jinyi Yang, Jaclyn B. Champagne, Roberto Decarli, Xiaohui Fan, Eduardo Bañados, Zheng Cai, Luis Colina, Eiichi Egami, Joseph F. Hennawi, Xiangyu Jin, Hyunsung D. Jun, Yana Khusanova, Mingyu Li, Zihao Li, Xiaojing Lin, Weizhe Liu, Romain A. Meyer, Maria A. Pudoka, George H. Rieke, Yue Shen, Wei Leong Tee, Bram Venemans, Fabian Walter , et al. (3 additional authors not shown)

Abstract: We present a stringent measurement of the dust-obscured star-formation rate density (SFRD) at $z=4-6$ from the ASPIRE JWST Cycle-1 medium and ALMA Cycle-9 large program. We obtained JWST/NIRCam grism spectroscopy and ALMA 1.2-mm continuum map along 25 independent quasar sightlines, covering a total survey area of $\sim$35 arcmin$^2$ where we search for dusty star-forming galaxies (DSFGs) at… ▽ More We present a stringent measurement of the dust-obscured star-formation rate density (SFRD) at $z=4-6$ from the ASPIRE JWST Cycle-1 medium and ALMA Cycle-9 large program. We obtained JWST/NIRCam grism spectroscopy and ALMA 1.2-mm continuum map along 25 independent quasar sightlines, covering a total survey area of $\sim$35 arcmin$^2$ where we search for dusty star-forming galaxies (DSFGs) at $z = 0 - 7$. We identify eight DSFGs in seven fields at $z=4-6$ through the detection of H$α$ or [O III] $λ$5008 lines, including fainter lines such as H$β$, [O III] $λ$4960, [N II] $λ$6585, [S II] $λλ$6718,6733 for six sources. With this spectroscopically complete DSFG sample at $z=4-6$ and negligible impact from cosmic variance (shot noise), we measure the infrared luminosity function (IRLF) down to $L_\mathrm{IR} \sim 2\times10^{11}$ $L_\odot$. We find flattening of IRLF at $z=4-6$ towards the faint end (power-law slope $α= 0.59_{-0.45}^{+0.39}$). We determine the dust-obscured cosmic SFRD at this epoch as $\log[ρ_\mathrm{SFR,IR} / (\mathrm{M}_\odot\,\mathrm{yr}^{-1}\,\mathrm{Mpc}^{-3})] = -1.52_{-0.13}^{+0.14}$. This is significantly higher than previous determination using ALMA data in the Hubble Ultra Deep Field, which is void of DSFGs at $z=4-6$ because of strong cosmic variance (shot noise). We conclude that the majority ($66\pm7$%) of cosmic star formation at $z \sim 5$ is still obscured by dust. We also discuss the uncertainty of SFRD propagated from far-IR spectral energy distribution and IRLF at the bright end, which will need to be resolved with future ALMA and JWST observations. △ Less

Submitted 9 December, 2024; originally announced December 2024.

Comments: 27 pages, 13 figures, 3 tables. Accepted for publication in ApJ

The host galaxies of radio-loud quasars at z>5 with ALMA

Authors: C. Mazzucchelli, R. Decarli, S. Belladitta, E. Bañados, R. A. Meyer, T. Connor, E. Momjian, S. Rojas-Ruiz, A. -C. Eilers, Y. Khusanova, E. P. Farina, A. B. Drake, F. Walter, F. Wang, M. Onoue, B. P. Venemans

Abstract: The interaction between radio-jets and quasar host galaxies plays a paramount role in quasar/galaxy co-evolution. However, very little has been known so far about this interaction at very high-z. Here, we present new Atacama Large Millimeter/submillimeter Array (ALMA) observations in Band 7 and Band 3 of six radio-loud quasars' host galaxies at $z > 5$. We recover [CII] 158 $μ$m line and underlyin… ▽ More The interaction between radio-jets and quasar host galaxies plays a paramount role in quasar/galaxy co-evolution. However, very little has been known so far about this interaction at very high-z. Here, we present new Atacama Large Millimeter/submillimeter Array (ALMA) observations in Band 7 and Band 3 of six radio-loud quasars' host galaxies at $z > 5$. We recover [CII] 158 $μ$m line and underlying dust continuum emission at $>2σ$ for five sources, while we obtain upper limits for the CO(6-5) emission line and continuum for the remaining source. At the spatial resolution of our observations ($\sim$1.0"-1.4"), we do not recover perturbed/extended morphologies or kinematics, signatures of potential mergers. These galaxies already host large quantities of gas, with [CII]-based star formation rates of $30-400 M_{\odot} $yr$^{-1}$. Building their radio/sub-mm spectral energy distributions (SEDs), we find that in at least four cases the 1mm continuum intensity arises from a combination of synchrotron and dust emission, with an initial estimation of synchrotron contribution at 300 GHz of $\gtrsim$10%. We compare the properties of the sources inspected here with a large collection of radio-quiet sources from the literature, as well as a sample of radio-loud quasars from previous studies, at comparable redshift. We recover a potential mild decrease in $L_{\rm [CII]}$ for the radio-loud sources, which might be due to a suppression of the cool gas emission due to the radio-jets. We do not find any [CII]-emitting companion galaxy candidate around the five radio-loud quasars observed in Band 7: given the depth of our dataset, this result is still consistent with that observed around radio-quiet quasars. Further higher-spatial resolution observations, over a larger frequency range, of high-z radio-loud quasars hosts will allow for a better understanding of the physics of such sources. △ Less

Submitted 18 November, 2024; originally announced November 2024.

Comments: 20 pages; 11 figures; accepted for publication in A&A

Journal ref: A&A 694, A171 (2025)

Broad-Line AGN at 3.5<z<6: The Black Hole Mass Function and a Connection with Little Red Dots

Authors: Anthony J. Taylor, Steven L. Finkelstein, Dale D. Kocevski, Junehyoung Jeon, Volker Bromm, Ricardo O. Amorin, Pablo Arrabal Haro, Bren E. Backhaus, Micaela B. Bagley, Eduardo Bañados, Rachana Bhatawdekar, Madisyn Brooks, Antonello Calabro, Oscar A. Chavez Ortiz, Yingjie Cheng, Nikko J. Cleri, Justin W. Cole, Kelcey Davis, Mark Dickinson, Callum Donnan, James S. Dunlop, Richard S. Ellis, Vital Fernandez, Adriano Fontana, Seiji Fujimoto , et al. (26 additional authors not shown)

Abstract: We present a sample of 50 H-alpha detected broad-line active galactic nuclei (BLAGN) at redshifts 3.5<z<6.8 using data from the CEERS and RUBIES surveys. We select these sources directly from JWST/NIRSpec G395M/F290LP spectra. We use a multi-step pre-selection and a Bayesian fitting procedure to ensure a high-quality sample of sources with broad Balmer lines and narrow forbidden lines. We compute… ▽ More We present a sample of 50 H-alpha detected broad-line active galactic nuclei (BLAGN) at redshifts 3.5<z<6.8 using data from the CEERS and RUBIES surveys. We select these sources directly from JWST/NIRSpec G395M/F290LP spectra. We use a multi-step pre-selection and a Bayesian fitting procedure to ensure a high-quality sample of sources with broad Balmer lines and narrow forbidden lines. We compute rest-frame ultraviolet and optical spectral slopes for these objects, and determine that 10 BLAGN in our sample are also little red dots (LRDs). These LRD BLAGN, when examined in aggregate, show broader H-alpha line profiles and a higher fraction of broad-to-narrow component H-alpha emission than non-LRD BLAGN. Moreover, we find that ~66% of these objects are intrinsically reddened (beta (optical)>0), independent of the contributions of emission lines to the broadband photometry. We construct the black hole (BH) mass function at 3.5<z<6 after computing robust observational and line detection completeness corrections. This BH mass function shows broad agreement with both recent JWST/NIRSpec and JWST/NIRCam WFSS based BH mass functions, though we extend these earlier results to log(M(BH)/M(sun)) < 7. The derived BH mass function is consistent with a variety of theoretical models, indicating that the observed abundance of black holes in the early universe is not discrepant with physically-motivated predictions. The BH mass function shape resembles a largely featureless power-law, suggesting that any signature from black-hole seeding has been lost by redshift z~5-6. Finally, we compute the BLAGN UV luminosity function and find good agreement with JWST-detected BLAGN samples from recent works, finding that BLAGN hosts constitute <10% of the total observed UV luminosity at all but the brightest luminosities. △ Less

Submitted 14 May, 2025; v1 submitted 10 September, 2024; originally announced September 2024.

Comments: V1: 28 pages, 14 figures, 4 tables. Submitted to ApJ. V2: 32 pages, 14 figures, 4 tables. Accepted for publication in ApJ

Far-Infrared and [CII] observations of a z=7 blazar

Authors: Eduardo Banados, Yana Khusanova, Roberto Decarli, Emmanuel Momjian, Fabian Walter, Thomas Connor, Christopher Carilli, Chiara Mazzucchelli, Sofia Rojas-Ruiz, Bram Venemans

Abstract: We present millimeter observations of the host galaxy of the most distant blazar known, VLASSJ041009.05-013919.88 (hereafter J0410-0139) at z=7, using ALMA and NOEMA observations. The ALMA data reveal a 2e42 erg/s [CII] 158um emission line at z=6.9964 with a [CII]-inferred star-formation rate of 58 Msun/yr. We estimate a dynamical mass of 4.6e9 Msun, implying a black hole mass to host a dynamical… ▽ More We present millimeter observations of the host galaxy of the most distant blazar known, VLASSJ041009.05-013919.88 (hereafter J0410-0139) at z=7, using ALMA and NOEMA observations. The ALMA data reveal a 2e42 erg/s [CII] 158um emission line at z=6.9964 with a [CII]-inferred star-formation rate of 58 Msun/yr. We estimate a dynamical mass of 4.6e9 Msun, implying a black hole mass to host a dynamical mass ratio of 0.15. The 238 GHz continuum (rest-frame IR) decreased by ~33% from the NOEMA to the ALMA observations taken ~10 months apart. The VLA 3-10 GHz radio flux densities showed a ~37% decrease in a similar time frame, suggesting a causal connection. At face value, J0410-0139 would have the lowest [CII]-to-IR luminosity ratio of a z>5.7 quasar reported to date (~1e-4). However, if only <20% of the measured IR luminosity were due to thermal emission from dust, the [CII]-to-IR luminosity ratio would be typical of (U)LIRGS, and the star formation rates derived from [CII] and IR luminosities would be consistent. These results provide further evidence that synchrotron emission significantly contributes to the observed rest-frame IR emission of J0410-0139, similar to what has been reported in some radio-loud AGN at z<1. △ Less

Submitted 22 August, 2024; originally announced August 2024.

Comments: Version after addressing referee report. See also companion paper: arXiv:2407.07236

Journal ref: 2024 ApJL 977 L46

A blazar in the epoch of reionization

Authors: Eduardo Banados, Emmanuel Momjian, Thomas Connor, Silvia Belladitta, Roberto Decarli, Chiara Mazzucchelli, Bram P. Venemans, Fabian Walter, Feige Wang, Zhang-Liang Xie, Aaron J. Barth, Anna-Christina Eilers, Xiaohui Fan, Yana Khusanova, Jan-Torge Schindler, Daniel Stern, Jinyi Yang, Irham Taufik Andika, Chris Carilli, Emanuele P. Farina, Andrew Fabian, Joseph F. Hennawi, Antonio Pensabene, Sofia Rojas-Ruiz

Abstract: Relativistic jets are thought to play a crucial role in the formation and evolution of massive galaxies and supermassive black holes. Blazars, which are quasars with jets aligned along our line of sight, provide insights into the jetted population and have been observed up to redshifts of z=6.1. Here, we report the discovery and multi-wavelength characterization of the blazar VLASS J041009.05-0139… ▽ More Relativistic jets are thought to play a crucial role in the formation and evolution of massive galaxies and supermassive black holes. Blazars, which are quasars with jets aligned along our line of sight, provide insights into the jetted population and have been observed up to redshifts of z=6.1. Here, we report the discovery and multi-wavelength characterization of the blazar VLASS J041009.05-013919.88 at z=7 (Universe's age ~750 Myr), powered by a ~7x10^8 Msun black hole. The presence of this high-redshift blazar implies a large population of similar but unaligned jetted sources in the early Universe. Our findings suggest two possible scenarios: in one, the jet in J0410-0139 is intrinsically low-power but appears highly luminous due to relativistic beaming, suggesting that most UV-bright quasars at this redshift host jets. Alternatively, if J0410-0139 represents an intrinsically powerful radio source, there should be hundreds to thousands of radio-quiet quasars at z~7 with properties similar to J0410-0139, a prediction in tension with observed quasar densities based on their UV luminosity function. These results support the hypothesis that rapid black hole growth in the early Universe may be driven by jet-enhanced or obscured super-Eddington accretion, potentially playing a key role in forming massive black holes during the epoch of reionization. △ Less

Submitted 16 December, 2024; v1 submitted 9 July, 2024; originally announced July 2024.

Comments: Updated to match accepted/final version in Nature Astronomy

Diverse molecular gas excitations in quasar host galaxies at z \sim 6

Authors: Jianan Li, Ran Wang, Antonio Pensabene, Fabian Walter, Bram P. Venemans, Roberto Decarli, Eduardo Bañados, Pierre Cox, Roberto Neri, Alain Omont, Zheng Cai, Yana Khusanova, Fuxiang Xu, Dominik Riechers, Jeff wagg, Yali Shao, Yuanqi Liu, Karl M. Menten, Qiong Li, Xiaohui Fan

Abstract: We present observations using the NOrthern Extended Millimetre Array (NOEMA) of CO and $\rm H_{2}O$ emission lines, and the underlying dust continuum in two quasars at $z \sim 6$, i.e., P215-16 at $z$ = 5.78 and J1429+5447 at $z$ = 6.18. Notably, among all published CO SLEDs of quasars at $z \sim 6$, the two systems reveal the highest and the lowest CO level of excitation, respectively. Our radiat… ▽ More We present observations using the NOrthern Extended Millimetre Array (NOEMA) of CO and $\rm H_{2}O$ emission lines, and the underlying dust continuum in two quasars at $z \sim 6$, i.e., P215-16 at $z$ = 5.78 and J1429+5447 at $z$ = 6.18. Notably, among all published CO SLEDs of quasars at $z \sim 6$, the two systems reveal the highest and the lowest CO level of excitation, respectively. Our radiative transfer modeling of the CO SLED of P215-16 suggests that the molecular gas heated by AGN could be a plausible origin for the high CO excitation. For J1429+5447, we obtain the first well-sampled CO SLED (from transitions from 2-1 to 10-9) of a radio-loud quasar at $z\gtrsim 6$. Analysis of the CO SLED suggests that a single photo-dissociation region (PDR) component could explain the CO excitation in the radio-loud quasar J1429+5447. This work highlights the utility of the CO SLED in uncovering the ISM properties in these young quasar-starburst systems at the highest redshift. The diversity of the CO SLEDs reveals the complexities in gas conditions and excitation mechanisms at their early evolutionary stage. △ Less

Submitted 9 January, 2024; originally announced January 2024.

Comments: Accepted for publication in Apj

Protoclusters as Drivers of Stellar Mass Growth in the Early Universe, a Case Study: Taralay -- a Massive Protocluster at z ~ 4.57

Authors: Priti Staab, Brian C. Lemaux, Ben Forrest, Ekta Shah, Olga Cucciati, Lori Lubin, Roy R. Gal, Denise Hung, Lu Shen, Finn Giddings, Yana Khusanova, Giovanni Zamorani, Sandro Bardelli, Letizia Pasqua Cassara, Paolo Cassata, Yi-Kuan Chiang, Yoshinobu Fudamoto, Shuma Fukushima, Bianca Garilli, Mauro Giavalisco, Carlotta Gruppioni, Lucia Guaita, Gayathri Gururajan, Nimish Hathi, Daichi Kashino , et al. (4 additional authors not shown)

Abstract: Simulations predict that the galaxy populations inhabiting protoclusters may contribute considerably to the total amount of stellar mass growth of galaxies in the early universe. In this study, we test these predictions observationally, focusing on the Taralay protocluster (formerly PCl J1001+0220) at $z \sim 4.57$ in the COSMOS field. Leveraging data from the Charting Cluster Construction with VU… ▽ More Simulations predict that the galaxy populations inhabiting protoclusters may contribute considerably to the total amount of stellar mass growth of galaxies in the early universe. In this study, we test these predictions observationally, focusing on the Taralay protocluster (formerly PCl J1001+0220) at $z \sim 4.57$ in the COSMOS field. Leveraging data from the Charting Cluster Construction with VUDS and ORELSE (C3VO) survey, we spectroscopically confirmed 44 galaxies within the adopted redshift range of the protocluster ($4.48 < z < 4.64$) and incorporate an additional 18 such galaxies from ancillary spectroscopic surveys. Using a density mapping technique, we estimate the total mass of Taralay to be $\sim 1.7 \times 10^{15}$ M$_\odot$, sufficient to form a massive cluster by the present day. By comparing the star formation rate density (SFRD) within the protocluster (SFRD$_\text{pc}$) to that of the coeval field (SFRD$_\text{field}$), we find that SFRD$_\text{pc}$ surpasses the SFRD$_\text{field}$ by $Δ$log(SFRD/$M_\odot$ yr$^{-1}$ Mpc$^{-3}$) = $1.08 \pm 0.32$ (or $\sim$ 12$\times$). The observed contribution fraction of protoclusters to the cosmic SFRD adopting Taralay as a proxy for typical protoclusters is $33.5\%^{+8.0\%}_{-4.3\%}$, a value $\sim$2$σ$ in excess of the predictions from simulations. Taralay contains three peaks that are $5σ$ above the average density at these redshifts. Their SFRD is $\sim$0.5 dex higher than the value derived for the overall protocluster. We show that 68% of all star formation in the protocluster takes place within these peaks, and that the innermost regions of the peaks encase $\sim 50\%$ of the total star formation in the protocluster. This study strongly suggests that protoclusters drive stellar mass growth in the early universe and that this growth may proceed in an inside-out manner. △ Less

Submitted 18 December, 2023; originally announced December 2023.

Comments: 26 pages, 14 figures, 10 tables

A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE): JWST Reveals a Filamentary Structure around a z=6.61 Quasar

Authors: Feige Wang, Jinyi Yang, Joseph F. Hennawi, Xiaohui Fan, Fengwu Sun, Jaclyn B. Champagne, Tiago Costa, Melanie Habouzit, Ryan Endsley, Zihao Li, Xiaojing Lin, Romain A. Meyer, Jan-Torge Schindler, Yunjing Wu, Eduardo Bañados, Aaron J. Barth, Aklant K. Bhowmick, Rebekka Bieri, Laura Blecha, Sarah Bosman, Zheng Cai, Luis Colina, Thomas Connor, Frederick B. Davies, Roberto Decarli , et al. (34 additional authors not shown)

Abstract: We present the first results from the JWST ASPIRE program (A SPectroscopic survey of biased halos In the Reionization Era). This program represents an imaging and spectroscopic survey of 25 reionization-era quasars and their environments by utilizing the unprecedented capabilities of NIRCam Wide Field Slitless Spectroscopy (WFSS) mode. ASPIRE will deliver the largest ($\sim280~{\rm arcmin}^2$) gal… ▽ More We present the first results from the JWST ASPIRE program (A SPectroscopic survey of biased halos In the Reionization Era). This program represents an imaging and spectroscopic survey of 25 reionization-era quasars and their environments by utilizing the unprecedented capabilities of NIRCam Wide Field Slitless Spectroscopy (WFSS) mode. ASPIRE will deliver the largest ($\sim280~{\rm arcmin}^2$) galaxy redshift survey at 3-4 $μ$m among JWST Cycle-1 programs and provide extensive legacy values for studying the formation of the earliest supermassive black holes (SMBHs), the assembly of galaxies, early metal enrichment, and cosmic reionization. In this first ASPIRE paper, we report the discovery of a filamentary structure traced by the luminous quasar J0305-3150 and ten [OIII] emitters at $z=6.6$. This structure has a 3D galaxy overdensity of $δ_{\rm gal}=12.6$ over 637 cMpc$^3$, one of the most overdense structures known in the early universe, and could eventually evolve into a massive galaxy cluster. Together with existing VLT/MUSE and ALMA observations of this field, our JWST observations reveal that J0305-3150 traces a complex environment where both UV-bright and dusty galaxies are present, and indicate that the early evolution of galaxies around the quasar is not simultaneous. In addition, we discovered 31 [OIII] emitters in this field at other redshifts, $5.3<z<6.7$, with half of them situated at $z\sim5.4$ and $z\sim6.2$. This indicates that star-forming galaxies, such as [OIII] emitters, are generally clustered at high redshifts. These discoveries demonstrate the unparalleled redshift survey capabilities of NIRCam WFSS and the potential of the full ASPIRE survey dataset. △ Less

Submitted 19 April, 2023; originally announced April 2023.

Comments: accepted for publication in ApJL

A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE): A First Look at the Rest-frame Optical Spectra of $z > 6.5$ Quasars Using JWST

Authors: Jinyi Yang, Feige Wang, Xiaohui Fan, Joseph F. Hennawi, Aaron J. Barth, Eduardo Bañados, Fengwu Sun, Weizhe Liu, Zheng Cai, Linhua Jiang, Zihao Li, Masafusa Onoue, Jan-Torge Schindler, Yue Shen, Yunjing Wu, Aklant K. Bhowmick, Rebekka Bieri, Laura Blecha, Sarah Bosman, Jaclyn B. Champagne, Luis Colina, Thomas Connor, Tiago Costa, Frederick B. Davies, Roberto Decarli , et al. (31 additional authors not shown)

Abstract: Studies of rest-frame optical emission in quasars at $z>6$ have historically been limited by the wavelengths accessible by ground-based telescopes. The James Webb Space Telescope (JWST) now offers the opportunity to probe this emission deep into the reionization epoch. We report the observations of eight quasars at $z>6.5$ using the JWST/NIRCam Wide Field Slitless Spectroscopy, as a part of the ''… ▽ More Studies of rest-frame optical emission in quasars at $z>6$ have historically been limited by the wavelengths accessible by ground-based telescopes. The James Webb Space Telescope (JWST) now offers the opportunity to probe this emission deep into the reionization epoch. We report the observations of eight quasars at $z>6.5$ using the JWST/NIRCam Wide Field Slitless Spectroscopy, as a part of the ''A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE)" program. Our JWST spectra cover the quasars' emission between rest frame $\sim$ 4100 and 5100 Å. The profiles of these quasars' broad H$β$ emission lines span a FWHM from 3000 to 6000 $\rm{km~s^{-1}}$. The H$β$-based virial black hole (BH) masses, ranging from 0.6 to 2.1 billion solar masses, are generally consistent with their MgII-based BH masses. The new measurements based on the more reliable H$β$ tracer thus confirm the existence of billion solar-mass BHs in the reionization epoch. In the observed [OIII] $λλ$4960,5008 doublets of these luminous quasars, broad components are more common than narrow core components ($\le~1200~\rm{km~s^{-1}}$), and only one quasar shows stronger narrow components than broad. Two quasars exhibit significantly broad and blueshifted [OIII] emission, thought to trace galactic-scale outflows, with median velocities of $-610~\rm{km~s^{-1}}$ and $-1430~\rm{km~s^{-1}}$ relative to the [CII] $158\,μ$m line. All eight quasars show strong optical FeII emission, and follow the Eigenvector 1 relations defined by low-redshift quasars. The entire ASPIRE program will eventually cover 25 quasars and provide a statistical sample for the studies of the BHs and quasar spectral properties. △ Less

Submitted 19 April, 2023; originally announced April 2023.

Comments: 13 pages, 4 figures, accepted for publication in ApJL

The Pan-STARRS1 z>5.6 quasar survey II: Discovery of 55 Quasars at 5.6<z<6.5

Authors: Eduardo Banados, Jan-Torge Schindler, Bram P. Venemans, Thomas Connor, Roberto Decarli, Emanuele Paolo Farina, Chiara Mazzucchelli, Romain A. Meyer, Daniel Stern, Fabian Walter, Xiaohui Fan, Joseph F. Hennawi, Yana Khusanova, Nidia Morrell, Riccardo Nanni, Gael Noirot, Antonio Pensabene, Hans-Walter Rix, Joseph Simon, Gijs A. Verdoes Kleijn, Zhang-Liang Xie, Da-Ming Yang, Andrew Connor

Abstract: The identification of bright quasars at z>6 enables detailed studies of supermassive black holes, massive galaxies, structure formation, and the state of the intergalactic medium within the first billion years after the Big Bang. We present the spectroscopic confirmation of 55 quasars at redshifts 5.6<z<6.5 and UV magnitudes -24.5<M1450<-28.5 identified in the optical Pan-STARRS1 and near-IR VIKIN… ▽ More The identification of bright quasars at z>6 enables detailed studies of supermassive black holes, massive galaxies, structure formation, and the state of the intergalactic medium within the first billion years after the Big Bang. We present the spectroscopic confirmation of 55 quasars at redshifts 5.6<z<6.5 and UV magnitudes -24.5<M1450<-28.5 identified in the optical Pan-STARRS1 and near-IR VIKING surveys (48 and 7, respectively). Five of these quasars have been independently discovered in other studies. The quasar sample shows an extensive range of physical properties, including 17 objects with weak emission lines, ten broad absorption line quasars, and five with strong radio emission (radio-loud quasars). There are also a few notable sources in the sample, including a blazar candidate at z=6.23, a likely gravitationally lensed quasar at z=6.41, and a z=5.84 quasar in the outskirts of the nearby (D~3 Mpc) spiral galaxy M81. The blazar candidate remains undetected in NOEMA observations of the [CII] and underlying emission, implying a star-formation rate <30-70 Msun/yr. A significant fraction of the quasars presented here lies at the foundation of the first measurement of the z~6 quasar luminosity function from Pan-STARRS1 (introduced in a companion paper). The quasars presented here will enable further studies of the high-redshift quasar population with current and future facilities. △ Less

Submitted 8 December, 2022; originally announced December 2022.

Comments: Version after addressing referee report. See companion paper by Schindler et al

ALPINE: A Large Survey to Understand Teenage Galaxies

Authors: A. L. Faisst, L. Yan, M. Béthermin, P. Cassata, M. Dessauges-Zavadsky, Y. Fudamoto, M. Ginolfi, C. Gruppioni, G. Jones, Y. Khusanova, O. LeFèvre, F. Pozzi, M. Romano, D. Schaerer, J. Silverman, B. Vanderhoof

Abstract: A multiwavelength study of galaxies is important to understand their formation and evolution. Only in the recent past, thanks to the Atacama Large (Sub) Millimeter Array (ALMA), were we able to study the far-infrared (IR) properties of galaxies at high redshifts. In this article, we summarize recent research highlights and their significance to our understanding of early galaxy evolution from the… ▽ More A multiwavelength study of galaxies is important to understand their formation and evolution. Only in the recent past, thanks to the Atacama Large (Sub) Millimeter Array (ALMA), were we able to study the far-infrared (IR) properties of galaxies at high redshifts. In this article, we summarize recent research highlights and their significance to our understanding of early galaxy evolution from the ALPINE survey, a large program with ALMA to observe the dust continuum and 158um C+ emission of normal star-forming galaxies at z = 4-6. Combined with ancillary data at UV through near-IR wavelengths, ALPINE provides the currently largest multiwavelength sample of post-reionization galaxies and has advanced our understanding of (i) the demographics of C+ emission; (ii) the relation of star formation and C+ emission; (iii) the gas content; (iv) outflows and enrichment of the intergalactic medium; and (v) the kinematics, emergence of disks, and merger rates in galaxies at z > 4. ALPINE builds the basis for more detailed measurements with the next generation of telescopes, and places itself as an important post-reionization baseline sample to allow a continuous study of galaxies over 13 billion years of cosmic time. △ Less

Submitted 9 June, 2022; v1 submitted 7 June, 2022; originally announced June 2022.

Comments: 29 pages, 6 figures; Invited article for the special issue "Recent Advances in Infrared Galaxies and AGN", edited by Anna Sajina and Asantha R. Cooray, in Universe

Journal ref: Universe 2022, 8(6), 314

The [CII] and FIR properties of z>6 radio-loud quasars

Authors: Yana Khusanova, Eduardo Bañados, Chiara Mazzucchelli, Sofía Rojas-Ruiz, Emmanuel Momjian, Fabian Walter, Roberto Decarli, Bram Venemans, Emanuele Paolo Farina, Romain Meyer, Feige Wang, Jinyi Yang

Abstract: There are only five radio-loud quasars currently known within 1 Gyr from the Big Bang ($z>6$) and the properties of their host galaxies have not been explored in detail. We present a NOrthern Extended Millimeter Array (NOEMA) survey of [CII] (158 $μ$m) and underlying continuum emission of four $z>6$ radio-loud quasars, revealing their diverse properties. J0309+2717 ($z=6.10$) has a bright [CII] li… ▽ More There are only five radio-loud quasars currently known within 1 Gyr from the Big Bang ($z>6$) and the properties of their host galaxies have not been explored in detail. We present a NOrthern Extended Millimeter Array (NOEMA) survey of [CII] (158 $μ$m) and underlying continuum emission of four $z>6$ radio-loud quasars, revealing their diverse properties. J0309+2717 ($z=6.10$) has a bright [CII] line and underlying continuum, implying a starburst with a star-formation rate SFR=$340-1200$ $M_\odot$ yr$^{-1}$. J1429+5447 ($z=6.18$) has a SFR=$520-870$ $M_{\odot}$yr$^{-1}$ and its [CII] profile is consistent with two Gaussians, which could be interpreted as a galaxy merger. J1427+3312 ($z=6.12$) has a moderate SFR=$30-90$ $M_\odot$ yr$^{-1}$. Notably, this is a broad absorption line quasar and we searched for the presence of high-velocity outflows in the host galaxy. Although the NOEMA data reveal a tentative broad component of the [CII] line as wide as $\sim$1400~km~s$^{-1}$, the sensitivity of our current data is not sufficient to confirm it. Finally, P172+18 ($z=6.82$) is undetected in both [CII] and continuum, implying a SFR$<22-40$ $M_{\odot}$yr$^{-1}$. The broad range of SFRs is similar to what is observed in radio-quiet quasars at similar redshifts. If radio jets do not significantly contribute to both [CII] and IR luminosities, this suggest no feedback from the jet on the star formation in the host galaxy. △ Less

Submitted 20 April, 2022; v1 submitted 19 April, 2022; originally announced April 2022.

Comments: submitted to A&A

Journal ref: A&A 664, A39 (2022)

The Impact of Powerful Jets on the Far-infrared Emission of an Extreme Radio Quasar at z~6

Authors: Sofía Rojas-Ruiz, Eduardo Bañados, Marcel Neeleman, Thomas Connor, Anna-Christina Eilers, Bram P. Venemans, Yana Khusanova, Christopher L. Carilli, Chiara Mazzucchelli, Roberto Decarli, Emmanuel Momjian, Mladen Novak

Abstract: The interactions between radio jets and the interstellar medium play a defining role for the co-evolution of central supermassive black holes and their host galaxies, but observational constraints on these feedback processes are still very limited at redshifts $z > 2$. We investigate the radio-loud quasar PSO J352.4034-15.3373 at $z \sim 6$ at the edge of the Epoch of Reionization. This quasar is… ▽ More The interactions between radio jets and the interstellar medium play a defining role for the co-evolution of central supermassive black holes and their host galaxies, but observational constraints on these feedback processes are still very limited at redshifts $z > 2$. We investigate the radio-loud quasar PSO J352.4034-15.3373 at $z \sim 6$ at the edge of the Epoch of Reionization. This quasar is among the most powerful radio emitters and the first one with direct evidence of extended radio jets ($\sim$1.6 kpc) at these high redshifts. We analyze NOEMA and ALMA millimeter data targeting the CO (6-5) and [CII] far-infrared emission lines, respectively, and the underlying continuum. The broad $440\pm 80$ km s$^{-1}$ and marginally resolved [CII] emission line yields a systemic redshift of $z\!=\!5.832 \pm 0.001$. Additionally, we report a strong 215 MHz radio continuum detection, $88\pm 7$ mJy, using the GMRT. This measurement significantly improves the constraints at the low-frequency end of the spectral energy distribution of this quasar. In contrast to what is typically observed in high-redshift radio-quiet quasars, we show that cold dust emission alone cannot reproduce the millimeter continuum measurements. This is evidence that the strong synchrotron emission from the quasar contributes substantially to the emission even at millimeter (far-infrared in the rest-frame) wavelengths. This quasar is an ideal system to probe the effects of radio jets during the formation of a massive galaxy within the first Gyr of the Universe. △ Less

Submitted 9 August, 2021; originally announced August 2021.

Comments: 14 pages, 5 figures

The ALPINE-ALMA [CII] survey: Dust mass budget in the early Universe

Authors: F. Pozzi, F. Calura, Y. Fudamoto, M. Dessauges-Zavadsky, C. Gruppioni, M. Talia, G. Zamorani, M. Bethermin, A. Cimatti, A. Enia, Y. Khusanova, R. Decarli, O. Le Fevre, P. Capak, P. Cassata, A. L. Faisst, L. Yan, D. Schaerer, J. Silverman, S. Bardelli, M. Boquien, A. Enia, D. Narayanan, M. Ginolfi, N. P. Hathi , et al. (11 additional authors not shown)

Abstract: The dust content of normal galaxies and the dust mass density (DMD) at high-z (z>4) are unconstrained given the source confusion and the sensitivity limitations of previous observations. The ALMA Large Program to INvestigate [CII] at Early Times (ALPINE), which targeted 118 UV-selected star-forming galaxies at 4.4<z<5.9, provides a new opportunity to tackle this issue for the first time with a sta… ▽ More The dust content of normal galaxies and the dust mass density (DMD) at high-z (z>4) are unconstrained given the source confusion and the sensitivity limitations of previous observations. The ALMA Large Program to INvestigate [CII] at Early Times (ALPINE), which targeted 118 UV-selected star-forming galaxies at 4.4<z<5.9, provides a new opportunity to tackle this issue for the first time with a statistically robust dataset. We have exploited the rest-frame far-infrared (FIR) fluxes of the 23 continuum individually detected galaxies and stacks of continuum images to measure the dust content of the 118 UV-selected ALPINE galaxies. We have focused on the dust scaling relations and, by comparing them with predictions from chemical evolution models, we have probed the evolutionary stage of UV-selected galaxies at high-z. By using the observed correlation between the UV-luminosity and the dust mass, we have estimated the DMD of UV-selected galaxies at z~5, weighting the galaxies by means of the UV-luminosity function (UVLF). The derived DMD has been compared with the value we have estimated from the 10 ALPINE far-IR continuum blindly detected galaxies at the redshift of the ALPINE targets. The comparison of the observed dust scaling relations with chemical evolution models suggests that ALPINE galaxies are not likely progenitors of disc galaxies, but of intermediate and low mass proto-spheroids, resulting in present-day bulges of spiral or elliptical galaxies. Interestingly, this conclusion is in line with the independent morphological analysis, that shows that the majority (~70\%) of the dust-continuum detected galaxies have a disturbed morphology. The DMD obtained at z~5 from UV-selected sources is ~30% of the value obtained from blind far-IR selected sources, showing that the UV-selection misses the most dust-rich, UV-obscured galaxies. △ Less

Submitted 31 May, 2021; originally announced May 2021.

Comments: 16 pages, 6 figures. Accepted for publication in A&A

Journal ref: A&A 653, A84 (2021)

The less and the more IGM transmitted galaxies from z~2.7 to z~6 from VANDELS and VUDS

Authors: R. Thomas, L. Pentericci, O. Le Fèvre, A. M. Koekemoer, M. Castellano, A. Cimatti, F. Fontanot, A. Gargiulo, B. Garilli, M. Talia, R. Amorín, S. Bardelli, S. Cristiani, G. Cresci, M. Franco, J. P. U. Fynbo, N. P. Hathi, P. Hibon, Y. Khusanova, V. Le Brun, B. C. Lemaux, F. Mannucci, D. Schaerer, G. Zamorani, E. Zucca

Abstract: Aim. Our aim is to analyse the variance of the Inter-Galactic Medium transmission (IGM) by studying this parameter in the rest-frame UV spectra of a large sample of high redshift galaxies. Method. We make use of the VIMOS Ultra Deep Survey and the VANDELS public survey to have an insight into the far UV spectrum of $2.7<z<6$ galaxies. Using the SPARTAN fitting software, we estimate the IGM towards… ▽ More Aim. Our aim is to analyse the variance of the Inter-Galactic Medium transmission (IGM) by studying this parameter in the rest-frame UV spectra of a large sample of high redshift galaxies. Method. We make use of the VIMOS Ultra Deep Survey and the VANDELS public survey to have an insight into the far UV spectrum of $2.7<z<6$ galaxies. Using the SPARTAN fitting software, we estimate the IGM towards individual galaxies and then divide them in two sub-samples characterized by a transmission above or below the theoretical prescription. We create average spectra of combined VUDS and VANDELS data for each set of galaxies in seven redshift bins. Results. The resulting spectra clearly exhibit the variance of the IGM transmission that can be seen directly from high redshift galaxy observations. Computing the optical depth based on the IGM transmission, we find an excellent agreement with QSOs results. In addition, our measurements seem to suggest that there is a large dispersion of redshift where complete Gunn-Peterson Trough happens, depending on the line of sight. △ Less

Submitted 4 March, 2021; originally announced March 2021.

Comments: Accepted for publication on A&A

Journal ref: A&A 650, A63 (2021)

The VANDELS ESO public spectroscopic survey: final Data Release of 2087 spectra and spectroscopic measurements

Authors: B. Garilli, R. McLure, L. Pentericci, P. Franzetti, A. Gargiulo, A. Carnall, O. Cucciati, A. Iovino, R. Amorin, M. Bolzonella, A. Bongiorno, M. Castellano, A. Cimatti, M. Cirasuolo, F. Cullen, J. Dunlop, D. Elbaz, S. Finkelstein, A. Fontana, F. Fontanot, M. Fumana, L. Guaita, W. Hartley, M. Jarvis, S. Juneau , et al. (72 additional authors not shown)

Abstract: VANDELS is an ESO Public Spectroscopic Survey designed to build a sample of high signal to noise, medium resolution spectra of galaxies at redshift between 1 and 6.5. Here we present the final Public Data Release of the VANDELS Survey, comprising 2087 redshift measurements. We give a detailed description of sample selection, observations and data reduction procedures. The final catalogue reaches a… ▽ More VANDELS is an ESO Public Spectroscopic Survey designed to build a sample of high signal to noise, medium resolution spectra of galaxies at redshift between 1 and 6.5. Here we present the final Public Data Release of the VANDELS Survey, comprising 2087 redshift measurements. We give a detailed description of sample selection, observations and data reduction procedures. The final catalogue reaches a target selection completeness of 40% at iAB = 25. The high Signal to Noise ratio of the spectra (above 7 in 80% of the spectra) and the dispersion of 2.5Å allowed us to measure redshifts with high precision, the redshift measurement success rate reaching almost 100%. Together with the redshift catalogue and the reduced spectra, we also provide optical mid-IR photometry and physical parameters derived through SED fitting. The observed galaxy sample comprises both passive and star forming galaxies covering a stellar mass range 8.3< Log(M*/Msolar)<11.7. All catalogues and spectra are accessible through the survey database (http://vandels.inaf.it) where all information can be queried interactively, and via the ESO Archive (https://www.eso.org/qi/). △ Less

Submitted 19 January, 2021; originally announced January 2021.

Comments: 16 pages, 13 figures, accepted for publication in Astronomy & Astrophysics

Journal ref: A&A 647, A150 (2021)

The ALPINE-ALMA [CII] Survey: Obscured Star Formation Rate Density and Main Sequence of star-forming galaxies at z>4

Authors: Y. Khusanova, M. Béthermin, O. Le Fèvre, P. Capak, A. L. Faisst, D. Schaerer, J. D. Silverman, P. Cassata, L. Yan, M. Ginolfi, Y. Fudamoto, F. Loiacono, R. Amorin, S. Bardelli, M. Boquien, A. Cimatti, M. Dessauges-Zavadsky, C. Gruppioni, N. P. Hathi, G. C. Jones, A. M. Koekemoer, G. Lagache, R. Maiolino, B. C. Lemaux, P. Oesch , et al. (8 additional authors not shown)

Abstract: Star formation rate (SFR) measurements at z>4 have relied mostly on rest-frame far-ultraviolet (FUV) observations. The corrections for dust attenuation based on IRX-$β$ relation are highly uncertain and are still debated in the literature. Hence, rest-frame far-infrared (FIR) observations are necessary to constrain the dust-obscured component of the SFR. In this paper, we exploit the rest-frame FI… ▽ More Star formation rate (SFR) measurements at z>4 have relied mostly on rest-frame far-ultraviolet (FUV) observations. The corrections for dust attenuation based on IRX-$β$ relation are highly uncertain and are still debated in the literature. Hence, rest-frame far-infrared (FIR) observations are necessary to constrain the dust-obscured component of the SFR. In this paper, we exploit the rest-frame FIR continuum observations collected by the ALMA Large Program to INvestigate [CII] at Early times (ALPINE) to directly constrain the obscured SFR in galaxies at 4.4<z<5.9. We use stacks of continuum images to measure average infrared (IR) luminosities taking into account both detected and undetected sources. Based on these measurements, we measure the position of the main sequence of star-forming galaxies and the specific SFR (sSFR) at $z\sim4.5$ and $z\sim5.5$. We find that the main sequence and sSFR do not evolve significantly between $z\sim4.5$ and $z\sim5.5$, as opposed to lower redshifts. We develop a method to derive the obscured SFR density (SFRD) using the stellar masses or FUV-magnitudes as a proxy of FIR fluxes measured on the stacks and combining them with the galaxy stellar mass functions and FUV luminosity functions from the literature. We obtain consistent results independent of the chosen proxy. We find that the obscured fraction of SFRD is decreasing with increasing redshift but even at $z\sim5.5$ it constitutes around 61\% of the total SFRD. △ Less

Submitted 16 July, 2020; originally announced July 2020.

Comments: submitted to A&A, 19 pages

Journal ref: A&A 649, A152 (2021)

The Size and Pervasiveness of Ly$α$-UV Spatial Offsets in Star-Forming Galaxies at $z\sim6$

Authors: B. C. Lemaux, S. Fuller, M. Bradač, L. Pentericci, A. Hoag, V. Strait, T. Treu, C. Alvarez, P. Bolan, P. J. Gandhi, T. Jones, C. Mason, D. Pelliccia, B. Ribeiro, R. E. Ryan, K. B. Schmidt, E. Vanzella, Y. Khusanova, O. Le Fèvre, L. Guaita, N. P. Hathi, A. Koekemoer, J. Pforr

Abstract: We study the projected spatial offset between the ultraviolet continuum and Ly$α$ emission for 65 lensed and unlensed galaxies in the Epoch of Reionization ($5\leq z\leq7$), the first such study at these redshifts, in order to understand the potential for these offsets to confuse estimates of the Ly$α$ properties of galaxies observed in slit spectroscopy. While we find that ~40% of galaxies in our… ▽ More We study the projected spatial offset between the ultraviolet continuum and Ly$α$ emission for 65 lensed and unlensed galaxies in the Epoch of Reionization ($5\leq z\leq7$), the first such study at these redshifts, in order to understand the potential for these offsets to confuse estimates of the Ly$α$ properties of galaxies observed in slit spectroscopy. While we find that ~40% of galaxies in our sample show significant projected spatial offsets ($|Δ_{Lyα-UV}|$), we find a modest average offset of 0.61$\pm$0.08 kpc. A small fraction of our sample, ~10%, exhibits offsets of 2-4 kpc, sizes that are larger than the effective radii of typical galaxies at these redshifts. An internal comparison and a comparison to studies at lower redshift yielded no significant evidence of evolution of $|Δ_{Lyα-UV}|$ with redshift. In our own sample, UV-bright galaxies showed offsets a factor of three greater than their fainter counterparts, 0.89$\pm$0.18 vs. 0.27$\pm$0.05 kpc, respectively. We argue that offsets are likely not the result of merging processes, but are rather due to internal anisotropic processes resulting from stellar feedback facilitates Ly$α$ fluorescence and/or backscattering from nearby or outflowing gas. The reduction in the Ly$α$ flux due to offset effects for various observational setups was quantified through mock observations of simple simulations. It was found that the loss of Ly$α$ photons for galaxies with average offsets is not, if corrected for, a limiting factor for all but the narrowest slit widths (<0.4''). However, for the largest offsets, if such offsets are mostly perpendicular to the slit major axis, slit losses were found to be extremely severe in cases where slit widths of $\leq$1'' were employed, such as those planned for James Webb Space Telescope/NIRSpec observations. (abridged) △ Less

Submitted 27 April, 2021; v1 submitted 2 July, 2020; originally announced July 2020.

Comments: 21 pages, 7 figures, 2 tables. Updated with the accepted MNRAS version that includes minor changes to the text and two tables

The ALPINE-ALMA [CII] Survey: The nature, luminosity function and star formation history of dusty galaxies up to z~6

Authors: C. Gruppioni, M. Bethermin, F. Loiacono, O. Le Fevre, P. Capak, P. Cassata, A. L. Faisst, D. Schaerer, J. Silverman, L. Yan, S. Bardelli, M. Boquien, R. Carraro, A. Cimatti, M. Dessauges-Zavadsky, M. Ginolfi, S. Fujimoto, N. P. Hathi, G. C. Jones, Y. Khusanova, A. M. Koekemoer, G. Lagache, B. C. Lemaux, P. Oesch, F. Pozzi , et al. (8 additional authors not shown)

Abstract: We present the detailed characterisation of a sample of 56 sources serendipitously detected in ALMA band 7, as part of the ALMA Large Program to INvestigate CII at Early Times (ALPINE) in COSMOS and ECDFS. These sources have been used to derive the total infrared luminosity function (LF) and to estimate the cosmic star formation rate density (SFRD) up to z=6. We have looked for counterparts in all… ▽ More We present the detailed characterisation of a sample of 56 sources serendipitously detected in ALMA band 7, as part of the ALMA Large Program to INvestigate CII at Early Times (ALPINE) in COSMOS and ECDFS. These sources have been used to derive the total infrared luminosity function (LF) and to estimate the cosmic star formation rate density (SFRD) up to z=6. We have looked for counterparts in all the available multi-wavelength and photometric redshift catalogues, and in deeper near- and mid-IR source lists and maps, to identify optically dark sources with no matches in the public catalogues. Our ALMA blind survey allows us to push further the study of the nature and evolution of dusty galaxies at high-z, identifying luminous and massive sources to redshifts and faint luminosities never probed before by any far-infrared surveys. The ALPINE data are the first ones to sample the faint-end of the infrared LF, showing little evolution from z=2.5 to z=6, and a flat slope up to the highest redshifts. The SFRD obtained by integrating the luminosity function remains almost constant between z=2 and 6, and significantly higher than the optical/UV derivations, showing an important contribution of dusty galaxies and obscured star formation up to high-z. About 14 per cent of the ALPINE serendipitous continuum sources are optically+near-IR dark (six show a counterpart only in the mid-IR and no HST or near-IR identification, while two are detected as [CII] emitters at z=5). The six HST and near-IR dark galaxies with mid-IR counterpart contribute for about 17 per cent of the total SFRD at z=5 and dominate the high-mass end of the stellar mass function at z>3. △ Less

Submitted 30 September, 2020; v1 submitted 8 June, 2020; originally announced June 2020.

Comments: 26 pages, 18 figures. Accepted for publication in A&A

Journal ref: A&A 643, A8 (2020)

The ALPINE-ALMA [C II] survey: the luminosity function of serendipitous [C II] line emitters at $z\sim 5$

Authors: Federica Loiacono, Roberto Decarli, Carlotta Gruppioni, Margherita Talia, Andrea Cimatti, Gianni Zamorani, Francesca Pozzi, Lin Yan, Brian C. Lemaux, Dominik A. Riechers, Olivier Le Fèvre, Matthieu Béthermin, Peter Capak, Paolo Cassata, Andreas Faisst, Daniel Schaerer, John D. Silverman, Sandro Bardelli, Médéric Boquien, Sandra Burkutean, Miroslava Dessauges-Zavadsky, Yoshinobu Fudamoto, Seiji Fujimoto, Michele Ginolfi, Nimish P. Hathi , et al. (10 additional authors not shown)

Abstract: We present the first [CII] 158 $μ$m luminosity function (LF) at $z\sim 5$ from a sample of serendipitous lines detected in the ALMA Large Program to INvestigate [CII] at Early times (ALPINE). A search performed over the 118 ALPINE pointings revealed several serendipitous lines. Based on their fidelity, we selected 14 lines for the final catalog. According to the redshift of their counterparts, we… ▽ More We present the first [CII] 158 $μ$m luminosity function (LF) at $z\sim 5$ from a sample of serendipitous lines detected in the ALMA Large Program to INvestigate [CII] at Early times (ALPINE). A search performed over the 118 ALPINE pointings revealed several serendipitous lines. Based on their fidelity, we selected 14 lines for the final catalog. According to the redshift of their counterparts, we identified 8 out of 14 detections as [CII] lines at $z\sim 5$, and two as CO transitions at lower redshifts. The remaining 4 lines have an elusive identification in the available catalogs and we considered them as [CII] candidates. We used the 8 confirmed [CII] and the 4 [CII] candidates to build one of the first [CII] LFs at $z\sim 5$. We found that 11 out of these 12 sources have a redshift very similar to that of the ALPINE target in the same pointing, suggesting the presence of overdensities around the targets. Therefore, we split the sample in two (a "clustered" and "field" sub-sample) according to their redshift separation and built two separate LFs. Our estimates suggest that there could be an evolution of the [CII] LF between $z \sim 5$ and $z \sim 0$. By converting the [CII] luminosity to star formation rate we evaluated the cosmic star formation rate density (SFRD) at $z\sim 5$. The clustered sample results in a SFRD $\sim 10$ times higher than previous measurements from UV-selected galaxies. On the other hand, from the field sample (likely representing the average galaxy population) we derived a SFRD $\sim 1.6$ higher compared to current estimates from UV surveys but compatible within the errors. Because of the large uncertainties, observations of larger samples are necessary to better constrain the SFRD at $z\sim 5$. This study represents one of the first efforts aimed at characterizing the demography of [CII] emitters at $z\sim 5$ using a mm-selection of galaxies. △ Less

Submitted 8 June, 2020; originally announced June 2020.

Comments: 19 pages, 12 figures; submitted to Astronomy & Astrophysics

Journal ref: A&A 646, A76 (2021)

The ALPINE-ALMA [CII] survey: Molecular gas budget in the Early Universe as traced by [CII]

Authors: M. Dessauges-Zavadsky, M. Ginolfi, F. Pozzi, M. Béthermin, O. Le Fèvre, S. Fujimoto, J. D. Silverman, G. C. Jones, D. Schaerer, A. L. Faisst, Y. Khusanova, Y. Fudamoto, P. Cassata, F. Loiacono, P. L. Capak, L. Yan, R. Amorin, S. Bardelli, M. Boquien, A. Cimatti, C. Gruppioni, N. P. Hathi, E. Ibar, A. M. Koekemoer, B. C. Lemaux , et al. (10 additional authors not shown)

Abstract: The molecular gas content of normal galaxies at z>4 is poorly constrained, because the commonly used molecular gas tracers become hard to detect. We use the [CII]158um luminosity, recently proposed as a molecular gas tracer, to estimate the molecular gas content in a large sample of main-sequence star-forming galaxies at z=4.4-5.9, with a median stellar mass of 10^9.7 Msun, drawn from the ALMA Lar… ▽ More The molecular gas content of normal galaxies at z>4 is poorly constrained, because the commonly used molecular gas tracers become hard to detect. We use the [CII]158um luminosity, recently proposed as a molecular gas tracer, to estimate the molecular gas content in a large sample of main-sequence star-forming galaxies at z=4.4-5.9, with a median stellar mass of 10^9.7 Msun, drawn from the ALMA Large Program to INvestigate [CII] at Early times (ALPINE) survey. The agreement between molecular gas masses derived from [CII] luminosity, dynamical mass, and rest-frame 850um luminosity, extrapolated from the rest-frame 158um continuum, supports [CII] as a reliable tracer of molecular gas in our sample. We find a continuous decline of the molecular gas depletion timescale from z=0 to z=5.9, which reaches a mean value of (4.6+/-0.8)x10^8 yr at z~5.5, only a factor of 2-3 shorter than in present-day galaxies. This suggests a mild enhancement of star formation efficiency toward high redshifts, unless the molecular gas fraction significantly increases. Our estimates show that the rise in molecular gas fraction as reported previously, flattens off above z~3.7 to achieve a mean value of 63%+/-3 over z=4.4-5.9. This redshift evolution of the gas fraction is in line with the one of the specific star formation rate. We use multi-epoch abundance matching to follow the gas fraction evolution over cosmic time of progenitors of z=0 Milky Way-like galaxies in 10^13 Msun halos and of more massive z=0 galaxies in 10^14 Msun halos. Interestingly, the former progenitors show a monotonic decrease of the gas fraction with cosmic time, while the latter show a constant gas fraction from z=5.9 to z~2 and a decrease at z<2. We discuss three possible effects, namely outflows, halt of gas supplying, and over-efficient star formation, which may jointly contribute to the gas fraction plateau of the latter massive galaxies. △ Less

Submitted 22 April, 2020; originally announced April 2020.

Comments: 16 pages, 9 figures, 2 tables. Submitted to Astronomy & Astrophysics

Journal ref: A&A 643, A5 (2020)

The ALPINE-ALMA [CII] survey: Dust attenuation properties and obscured star formation at z~4.4-5.8

Authors: Yoshinobu Fudamoto, P. A. Oesch, A. Faisst, M. Bethermin, M. Ginolfi, Y. Khusanova, F. Loiacono, O. Le Fevre, P. Capak, D. Schaerer, J. D. Silverman, P. Cassata, L. Yan, R. Amorin, S. Bardelli, M. Boquien, A. Cimatti, M. Dessauges-Zavadsky, S. Fujimoto, C. Gruppioni, N. P. Hathi, E. Ibar, G. C. Jones, A. M. Koekemoer, G. Lagache , et al. (12 additional authors not shown)

Abstract: We present dust attenuation properties of spectroscopically confirmed star forming galaxies on the main sequence at a redshift of ~4.4-5.8. Our analyses are based on the far infrared continuum observations of 118 galaxies at rest-frame 158μm obtained with the Atacama Large Millimeter Array (ALMA) Large Program to INvestigate [CII] at Early times (ALPINE). We study the connection between the ultrav… ▽ More We present dust attenuation properties of spectroscopically confirmed star forming galaxies on the main sequence at a redshift of ~4.4-5.8. Our analyses are based on the far infrared continuum observations of 118 galaxies at rest-frame 158μm obtained with the Atacama Large Millimeter Array (ALMA) Large Program to INvestigate [CII] at Early times (ALPINE). We study the connection between the ultraviolet (UV) spectral slope ($β$), stellar mass (M_*), and infrared excess (IRX=L_IR/L_UV). Twenty-three galaxies are individually detected in the continuum at >3.5 sigma significance. We perform a stacking analysis using both detections and nondetections to study the average dust attenuation properties at z~4.4-5.8. The individual detections and stacks show that the IRX-$β$ relation at z~5 is consistent with a steeper dust attenuation curve than typically found at lower redshifts (z<4). The attenuation curve is similar to or even steeper than that of the extinction curve of the Small Magellanic Cloud (SMC). This systematic change of the IRX-$β$ relation as a function of redshift suggests an evolution of dust attenuation properties at z>4. Similarly, we find that our galaxies have lower IRX values, up to 1dex on average, at a fixed mass compared to previously studied IRX-M_* relations at z<4, albeit with significant scatter. This implies a lower obscured fraction of star formation than at lower redshifts. Our results suggest that dust properties of UV-selected star forming galaxies at z>4 are characterised by (i) a steeper attenuation curve than at z<4, and (ii) a rapidly decreasing dust obscured fraction of star formation as a function of redshift. Nevertheless, even among this UV-selected sample, massive galaxies (log M_*/$M_\odot$>10) at z~5-6 already exhibit an obscured fraction of star formation of ~45%, indicating a rapid build-up of dust during the epoch of reionization. △ Less

Submitted 6 October, 2020; v1 submitted 22 April, 2020; originally announced April 2020.

Comments: 12 pages, 6 figures. accepted for publication in Astronomy & Astrophysics. Minor revisions

Journal ref: A&A 643, A4 (2020)

The ALPINE-ALMA [CII] Survey: data processing, catalogs, and statistical source properties

Authors: M. Bethermin, Y. Fudamoto, M. Ginolfi, F. Loiacono, Y. Khusanova, P. L. Capak, P. Cassata, A. Faisst, O. Le Fevre, D. Schaerer, J. D. Silverman, L. Yan, R. Amorin, S. Bardelli, M. Boquien, A. Cimatti, I. Davidzon, M. Dessauges-Zavadsky, S. Fujimoto, C. Gruppioni, N. P. Hathi, E. Ibar, G. C. Jones, A. M. Koekemoer, G. Lagache , et al. (11 additional authors not shown)

Abstract: The ALPINE-ALMA large program targets the [CII] 158 $μ$m line and the far-infrared continuum in 118 spectroscopically confirmed star-forming galaxies between z=4.4 and z=5.9. It represents the first large [CII] statistical sample built in this redshift range. We present details of the data processing and the construction of the catalogs. We detected 23 of our targets in the continuum. To derive ac… ▽ More The ALPINE-ALMA large program targets the [CII] 158 $μ$m line and the far-infrared continuum in 118 spectroscopically confirmed star-forming galaxies between z=4.4 and z=5.9. It represents the first large [CII] statistical sample built in this redshift range. We present details of the data processing and the construction of the catalogs. We detected 23 of our targets in the continuum. To derive accurate infrared luminosities and obscured star formation rates, we measured the conversion factor from the ALMA 158 $μ$m rest-frame dust continuum luminosity to the total infrared luminosity (L$_{\rm IR}$) after constraining the dust spectral energy distribution by stacking a photometric sample similar to ALPINE in ancillary single-dish far-infrared data. We found that our continuum detections have a median L$_{\rm IR}$ of 4.4$\times 10^{11}$ L$_\odot$. We also detected 57 additional continuum sources in our ALMA pointings. They are at lower redshift than the ALPINE targets, with a mean photometric redshift of 2.5$\pm$0.2. We measured the 850 $μ$m number counts between 0.35 and 3.5 mJy, improving the current interferometric constraints in this flux density range. We found a slope break in the number counts around 3 mJy with a shallower slope below this value. More than 40 % of the cosmic infrared background is emitted by sources brighter than 0.35 mJy. Finally, we detected the [CII] line in 75 of our targets. Their median [CII] luminosity is 4.8$\times$10$^8$ L$_\odot$ and their median full width at half maximum is 252 km/s. After measuring the mean obscured SFR in various [CII] luminosity bins by stacking ALPINE continuum data, we find a good agreement between our data and the local and predicted SFR-L$_{\rm [CII]}$ relations of De Looze et al. (2014) and Lagache et al. (2018). △ Less

Submitted 16 July, 2020; v1 submitted 3 February, 2020; originally announced February 2020.

Comments: 44 pages, 29 figures, 14 tables, accepted by A&A, ALPINE products released at https://cesam.lam.fr/a2c2s/, luminosities in table B2 corrected

Journal ref: A&A 643, A2 (2020)

The ALPINE-ALMA [CII] Survey: Multi-Wavelength Ancillary Data and Basic Physical Measurements

Authors: A. L. Faisst, D. Schaerer, B. C. Lemaux, P. A. Oesch, Y. Fudamoto, P. Cassata, M. Bethermin, P. L. Capak, O. Le Fevre, J. D. Silverman, L. Yan, M. Ginolfi, A. M. Koekemoer, L. Morselli, R. Amorin, S. Bardelli, M. Boquien, G. Brammer, A. Cimatti, M. Dessauges-Zavadsky, S. Fujimoto, C. Gruppioni, N. P. Hathi, S. Hemmati, E. Ibar , et al. (15 additional authors not shown)

Abstract: We present the ancillary data and basic physical measurements for the galaxies in the ALMA Large Program to Investigate C+ at Early Times (ALPINE) survey - the first large multi-wavelength survey which aims at characterizing the gas and dust properties of 118 main-sequence galaxies at redshifts 4.4 < z < 5.9 via the measurement of [CII]-emission at 158 micro-meter (64% at >3.5$σ$) and the surround… ▽ More We present the ancillary data and basic physical measurements for the galaxies in the ALMA Large Program to Investigate C+ at Early Times (ALPINE) survey - the first large multi-wavelength survey which aims at characterizing the gas and dust properties of 118 main-sequence galaxies at redshifts 4.4 < z < 5.9 via the measurement of [CII]-emission at 158 micro-meter (64% at >3.5$σ$) and the surrounding far-infrared (FIR) continuum in conjunction with a wealth of optical and near-infrared data. We outline in detail the spectroscopic data and selection of the galaxies as well as the ground- and space-based imaging products. In addition, we provide several basic measurements including stellar masses, star formation rates (SFR), rest-frame ultra-violet (UV) luminosities, UV continuum slopes ($β$), and absorption line redshifts, as well as H-alpha emission derived from Spitzer colors. We find that the ALPINE sample is representative of the 4 < z < 6 galaxy population selected by photometric methods and only slightly biased towards bluer colors ($Δβ$ ~ 0.2). Using [CII] as tracer of the systemic redshift (confirmed for one galaxy at z=4.5 out of 118 for which we obtained optical [OII]$λ$3727A emission), we confirm red shifted Ly-alpha emission and blue shifted absorption lines similar to findings at lower redshifts. By stacking the rest-frame UV spectra in the [CII] rest-frame we find that the absorption lines in galaxies with high specific SFR are more blue shifted, which could be indicative of stronger winds and outflows. △ Less

Submitted 12 March, 2020; v1 submitted 3 December, 2019; originally announced December 2019.

Comments: 48 pages, 33 figures, 7 tables (including Appendix), accepted for publication in ApJS

The Intergalactic medium transmission towards z>4 galaxies with VANDELS and the impact of dust attenuation

Authors: R. Thomas, L. Pentericci, O. Le Fèvre, G. Zamorani, D. Schaerer, R. Amorin, M. Castellano, A. C. Carnall, S. Cristiani, F. Cullen, S. L. Finkelstein, F. Fontanot, L. Guaita, P. Hibon, N. Hathi, J. P. U. Fynbo, Y. Khusanova, A. M. Koekemoer, D. McLeod, R. J. McLure, F. Marchi, L. Pozzetti, A. Saxena, M. Talia, M. Bolzonella

Abstract: Aims. Our aim is to estimate the intergalactic medium transmission towards UV-selected star-forming galaxies at redshift 4 and above and study the effect of the dust attenuation on these measurements. Methods. The ultra-violet spectrum of high redshift galaxies is a combination of their intrinsic emission and the effect of the Inter-Galactic medium (IGM) absorption along their line of sight. Usi… ▽ More Aims. Our aim is to estimate the intergalactic medium transmission towards UV-selected star-forming galaxies at redshift 4 and above and study the effect of the dust attenuation on these measurements. Methods. The ultra-violet spectrum of high redshift galaxies is a combination of their intrinsic emission and the effect of the Inter-Galactic medium (IGM) absorption along their line of sight. Using data coming from the unprecedented deep spectroscopy from the VANDELS ESO public survey carried out with the VIMOS instrument we compute both the dust extinction and the mean transmission of the IGM as well as its scatter from a set of 281 galaxies at z>3.87. Because of a degeneracy between the dust content of the galaxy and the IGM, we first estimate the stellar dust extinction parameter E(B-V) and study the result as a function of the dust prescription. Using these measurements as constraint for the spectral fit we estimate the IGM transmission Tr(Lyalpha). Both photometric and spectroscopic SED fitting are done using the SPectroscopy And photometRy fiTting tool for Astronomical aNalysis (SPARTAN) that is able to fit the spectral continuum of the galaxies as well as photometric data. Results. Using the classical Calzetti's attenuation law we find that E(B-V) goes from 0.11 at z=3.99 to 0.08 at z=5.15. These results are in very good agreement with previous measurements from the literature. We estimate the IGM transmission and find that the transmission is decreasing with increasing redshift from Tr(Lyalpha)=0.53 at z=3.99 to 0.28 at z=5.15. We also find a large standard deviation around the average transmission that is more than 0.1 at every redshift. Our results are in very good agreement with both previous measurements from AGN studies and with theoretical models. △ Less

Submitted 28 November, 2019; originally announced November 2019.

Comments: Accepted for publication in A&A

Journal ref: A&A 634, A110 (2020)

The ALPINE-ALMA [CII] survey: Star-formation-driven outflows and circumgalactic enrichment in the early Universe

Authors: M. Ginolfi, G. C. Jones, M. Bethermin, Y. Fudamoto, F. Loiacono, S. Fujimoto, O. Le Fevre, A. Faisst, D. Schaerer, P. Cassata, J. D. Silverman, Lin Yan, P. Capak, S. Bardelli, M. Boquien, R. Carraro, M. Dessauges-Zavadsky, M. Giavalisco, C. Gruppioni, E. Ibar, Y. Khusanova, B. C. Lemaux, R. Maiolino, D. Narayanan, P. Oesch , et al. (7 additional authors not shown)

Abstract: We study the efficiency of galactic feedback in the early Universe by stacking the [C II] 158 um emission in a large sample of normal star-forming galaxies at 4 < z < 6 from the ALMA Large Program to INvestigate [C II] at Early times (ALPINE) survey. Searching for typical signatures of outflows in the high-velocity tails of the stacked [C II] profile, we observe (i) deviations from a single-compon… ▽ More We study the efficiency of galactic feedback in the early Universe by stacking the [C II] 158 um emission in a large sample of normal star-forming galaxies at 4 < z < 6 from the ALMA Large Program to INvestigate [C II] at Early times (ALPINE) survey. Searching for typical signatures of outflows in the high-velocity tails of the stacked [C II] profile, we observe (i) deviations from a single-component Gaussian model in the combined residuals and (ii) broad emission in the stacked [C II] spectrum, with velocities of |v|<~ 500 km/s. The significance of these features increases when stacking the subset of galaxies with star formation rates (SFRs) higher than the median (SFRmed = 25 Msun/yr), thus confirming their star-formation-driven nature. The estimated mass outflow rates are comparable to the SFRs, yielding mass-loading factors of the order of unity (similarly to local star-forming galaxies), suggesting that star-formation-driven feedback may play a lesser role in quenching galaxies at z > 4. From the stacking analysis of the datacubes, we find that the combined [C II] core emission (|v|< 200 km/s) of the higher-SFR galaxies is extended on physical sizes of ~ 30 kpc (diameter scale), well beyond the analogous [C II] core emission of lower-SFR galaxies and the stacked far-infrared continuum. The detection of such extended metal-enriched gas, likely tracing circumgalactic gas enriched by past outflows, corroborates previous similar studies, confirming that baryon cycle and gas exchanges with the circumgalactic medium are at work in normal star-forming galaxies already at early epochs. △ Less

Submitted 22 November, 2019; v1 submitted 10 October, 2019; originally announced October 2019.

Comments: 16 pages, 10 figures. Accepted for publication in A&A

The ALPINE-ALMA [CII] Survey: A Triple Merger at z~4.56

Authors: G. C. Jones, M. Bethermin, Y. Fudamoto, M. Ginolfi, P. Capak, P. Cassata, A. Faisst, O. Le Fevre, D. Schaerer, J. Silverman, L. Yan, S. Bardelli, M. Boquien, A. Cimatti, M. Dessauges-Zavadsky, M. Giavalisco, C. Gruppioni, E. Ibar, Y. Khusanova, A. M. Koekemoer, B. C. Lemaux, F. Loiacono, R. Maiolino, P. A. Oesch, F. Pozzi , et al. (7 additional authors not shown)

Abstract: We report the detection of [CII]158um emission from a system of three closely-separated sources in the COSMOS field at z~4.56, as part of the ALMA Large Program to INvestigate CII at Early times (ALPINE). The two dominant sources are closely associated, both spatially (1.6"~11kpc) and in velocity (~100km/s), while the third source is slightly more distant (2.8"~18kpc, ~300km/s). The second stronge… ▽ More We report the detection of [CII]158um emission from a system of three closely-separated sources in the COSMOS field at z~4.56, as part of the ALMA Large Program to INvestigate CII at Early times (ALPINE). The two dominant sources are closely associated, both spatially (1.6"~11kpc) and in velocity (~100km/s), while the third source is slightly more distant (2.8"~18kpc, ~300km/s). The second strongest source features a slight velocity gradient, while no significant velocity gradient is seen in the other two sources. Using the observed [CII] luminosities, we derive a total log(SFR_[CII]/[Msol/year])=2.8+/-0.2, which may be split into contributions of 59%, 31%, and 10% from the central, east, and west sources, respectively. Comparison of these [CII] detections to recent zoom-in cosmological simulations suggests an ongoing major merger. We are thus witnessing a system in a major phase of mass build-up by merging, including an on-going major merger and an upcoming minor merger, which is expected to end up in a single massive galaxy by z~2.5. △ Less

Submitted 21 August, 2019; originally announced August 2019.

Comments: 5 pages, 4 figures, submitted to MNRASL

The UV and Ly$α$ Luminosity Functions of galaxies and the Star Formation Rate Density at the end of HI reionization from the VIMOS Ultra-Deep Survey (VUDS)

Authors: Y. Khusanova, O. Le Fèvre, P. Cassata, O. Cucciati, B. C. Lemaux, L. A. M. Tasca, R. Thomas, B. Garilli, V. Le Brun, D. Maccagni, L. Pentericci, G. Zamorani, R. Amorín, S. Bardelli, M. Castellano, L. P. Cassarà, A. Cimatti, M. Giavalisco, N. P. Hathi, O. Ilbert, A. M. Koekemoer, F. Marchi, J. Pforr, B. Ribeiro, D. Schaerer , et al. (3 additional authors not shown)

Abstract: We establish a robust statistical description of the star-forming galaxy population at the end of cosmic HI reionization ($5.0\le{}z\le6.6$) from a large sample of 52 galaxies with spectroscopically confirmed redshifts from the VIMOS UltraDeep Survey. We identify galaxies with Ly$α$ either in absorption or in emission, at variance with most spectroscopic samples in the literature where Ly$α$ emitt… ▽ More We establish a robust statistical description of the star-forming galaxy population at the end of cosmic HI reionization ($5.0\le{}z\le6.6$) from a large sample of 52 galaxies with spectroscopically confirmed redshifts from the VIMOS UltraDeep Survey. We identify galaxies with Ly$α$ either in absorption or in emission, at variance with most spectroscopic samples in the literature where Ly$α$ emitters dominate. We find that star-forming galaxies at these redshifts are distributed along a main sequence in the stellar mass vs. SFR plane. We report a flat evolution of the sSFR(z) in 3<z<6 compared to lower redshift measurements. UV-continuum slopes vary with luminosity, with a large dispersion. We determing UV and Ly$α$ luminosity functions using V$_{max}$ method and use them to derive star formation rate densities (SFRD). We find that both UV-derived and Ly$α$-derived SFRDs are in excellent agreement after correcting Ly$α$ luminosity density for IGM absorption. Our new SFRD measurements at a mean redshift z=5.6 confirm the steep decline of the SFRD at z>2. The bright end of the Ly$α$ luminosity function has a high number density, indicating a significant star formation activity concentrated in the brightest Ly$α$ emitters (LAE) at these redshifts. LAE with EW>25Å~contribute to about 75\% of the total UV-derived SFRD. While our analysis favors a low dust content in 5.0<z<6.6, uncertainties on the dust extinction correction and associated degeneracies in spectral fitting will remain an issue to estimate the total SFRD until future survey extending spectroscopy to the NIR rest-frame spectral domain, e.g. with JWST. △ Less

Submitted 5 March, 2019; originally announced March 2019.

Comments: 27 pages, submitted to A&A

Journal ref: A&A 634, A97 (2020)

The VANDELS ESO public spectroscopic survey

Authors: R. J. McLure, L. Pentericci, A. Cimatti, J. S. Dunlop, D. Elbaz, A. Fontana, K. Nandra, R. Amorin, M. Bolzonella, A. Bongiorno, A. C. Carnall, M. Castellano, M. Cirasuolo, O. Cucciati, F. Cullen, S. De Barros, S. L. Finkelstein, F. Fontanot, P. Franzetti, M. Fumana, A. Gargiulo, B. Garilli, L. Guaita, W. G. Hartley, A. Iovino , et al. (70 additional authors not shown)

Abstract: VANDELS is a uniquely-deep spectroscopic survey of high-redshift galaxies with the VIMOS spectrograph on ESO's Very Large Telescope (VLT). The survey has obtained ultra-deep optical (0.48 < lambda < 1.0 micron) spectroscopy of ~2100 galaxies within the redshift interval 1.0 < z < 7.0, over a total area of ~0.2 sq. degrees centred on the CANDELS UDS and CDFS fields. Based on accurate photometric re… ▽ More VANDELS is a uniquely-deep spectroscopic survey of high-redshift galaxies with the VIMOS spectrograph on ESO's Very Large Telescope (VLT). The survey has obtained ultra-deep optical (0.48 < lambda < 1.0 micron) spectroscopy of ~2100 galaxies within the redshift interval 1.0 < z < 7.0, over a total area of ~0.2 sq. degrees centred on the CANDELS UDS and CDFS fields. Based on accurate photometric redshift pre-selection, 85% of the galaxies targeted by VANDELS were selected to be at z>=3. Exploiting the red sensitivity of the refurbished VIMOS spectrograph, the fundamental aim of the survey is to provide the high signal-to-noise ratio spectra necessary to measure key physical properties such as stellar population ages, masses, metallicities and outflow velocities from detailed absorption-line studies. Using integration times calculated to produce an approximately constant signal-to-noise ratio (20 < t_int < 80 hours), the VANDELS survey targeted: a) bright star-forming galaxies at 2.4 < z < 5.5, b) massive quiescent galaxies at 1.0 < z < 2.5, c) fainter star-forming galaxies at 3.0 < z < 7.0 and d) X-ray/Spitzer-selected active galactic nuclei and Herschel-detected galaxies. By targeting two extragalactic survey fields with superb multi-wavelength imaging data, VANDELS will produce a unique legacy data set for exploring the physics underpinning high-redshift galaxy evolution. In this paper we provide an overview of the VANDELS survey designed to support the science exploitation of the first ESO public data release, focusing on the scientific motivation, survey design and target selection. △ Less

Submitted 14 May, 2018; v1 submitted 20 March, 2018; originally announced March 2018.

Comments: 19 pages, 9 figures, accepted for publication in MNRAS

The VANDELS ESO public spectroscopic survey: observations and first data release

Authors: L. Pentericci, R. J. McLure B. Garilli, O. Cucciati, P. Franzetti, A. Iovino, R. Amorin, M. Bolzonella, A. Bongiorno, A. C. Carnall, M. Castellano, A. Cimatti, M. Cirasuolo, F. Cullen, S. DeBarros, J. S. Dunlop, D. Elbaz, S. Finkelstein, A. Fontana, F. Fontanot, M. Fumana, A. Gargiulo, L. Guaita, W. Hartley, M. Jarvis, S. Juneau , et al. (71 additional authors not shown)

Abstract: This paper describes the observations and the first data release (DR1) of the ESO public spectroscopic survey "VANDELS, a deep VIMOS survey of the CANDELS CDFS and UDS fields". VANDELS' main targets are star-forming galaxies at 2.4<z<5.5 and massive passive galaxies at 1<z<2.5. By adopting a strategy of ultra-long exposure times, from 20 to 80 hours per source, VANDELS is designed to be the deepes… ▽ More This paper describes the observations and the first data release (DR1) of the ESO public spectroscopic survey "VANDELS, a deep VIMOS survey of the CANDELS CDFS and UDS fields". VANDELS' main targets are star-forming galaxies at 2.4<z<5.5 and massive passive galaxies at 1<z<2.5. By adopting a strategy of ultra-long exposure times, from 20 to 80 hours per source, VANDELS is designed to be the deepest ever spectroscopic survey of the high-redshift Universe. Exploiting the red sensitivity of the VIMOS spectrograph, the survey has obtained ultra-deep spectra covering the wavelength 4800-10000 A with sufficient signal-to-noise to investigate the astrophysics of high-redshift galaxy evolution via detailed absorption line studies. The VANDELS-DR1 is the release of all spectra obtained during the first season of observations and includes data for galaxies for which the total (or half of the total) scheduled integration time was completed. The release contains 879 individual objects with a measured redshift and includes fully wavelength and flux-calibrated 1D spectra, the associated error spectra, sky spectra and wavelength-calibrated 2D spectra. We also provide a catalog with the essential galaxy parameters, including spectroscopic redshifts and redshift quality flags. In this paper we present the survey layout and observations, the data reduction and redshift measurement procedure and the general properties of the VANDELS-DR1 sample. We also discuss the spectroscopic redshift distribution, the accuracy of the photometric redshifts and we provide some examples of data products. All VANDELS-DR1 data are publicly available and can be retrieved from the ESO archive. Two further data releases are foreseen in the next 2 years with a final release scheduled for June 2020 which will include improved re-reduction of the entire spectroscopic data set. (abridged) △ Less

Submitted 20 March, 2018; originally announced March 2018.

Comments: Submitted to A&A